The aim of this study was to compare the effect of slatted concrete floor and two different rubber covers for fully slatted floor pens on lying behaviour, joint swellings and cleanliness of finishing cattle. Eighty Swedish Holstein bulls of initially 250 kg were randomly divided into 16 boxes (10.4 m²) with three floor types (6 boxes slatted concrete, 5 boxes slatted rubber, 5 boxes rubber mats). At 400 kg the lightest bull in each box was taken out. In blind tests, cleanliness was recorded once a month and joint swellings were assessed at 650 kg, all according to a graded scale. Lying behaviour was continuously recorded for 12 h from video film at 250, 450 and 650 kg. Data were analysed with a mixed GLM model (cleanliness, reference slatted rubber), a logistic regression (joint swellings) and the Mann-Whitney-test (lying behaviour). Preliminary results for lying behaviour include recordings at 250 and 450 kg. The Ethical Committee on Animal Experiments Gothenburg approved the study. The appearance of joint swellings was influenced by floor type (Odds Ratioslatted concrete=39.4, Odds Ratiorubber mat=0.1, p<0.001). Animals on rubber mats were dirtier than on slatted concrete or slatted rubber (F=13.9, p<0.001). On both rubber floors there were more lying bouts than on slatted concrete at 250 kg (slatted rubber W=22.5, p=0.018; rubber mat W=21.5, p=0.012); there was no difference between the rubber floors. Furthermore, on both rubber floors there were less interrupted lying-down attempts than on slatted concrete at 450 kg (slatted rubber W=49, p=0.023; rubber mat W=48, p=0.036), with no difference between the rubber floors.
The results suggest that rubber covering improves welfare by diminishing the occurrence of joint swellings and decreasing the number of interrupted lying-down attempts. However, the use of rubber mats with less gap surface area results in dirtier bulls.